Pool cleaning device with improved bottom topography

ABSTRACT

The pool cleaning device of the invention has a housing bottom with an elliptically-beveled suction hole inlet and optional topographical features that facilitate smooth flow of water to and into the suction hole so as to improve capture of tree leaves and other debris. The optional topographical features include a sloped bottom along the leading edge to minimize the possibility of debris catching on the outer edge of the housing bottom, a bottom suction cavity with or without partitions designed to direct debris toward the elliptically-beveled suction hole inlet, and a fender that partially wraps around a cylindrical rotary brush along the leading edge of the housing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation-In-Part (CIP) of U.S. patentapplication Ser. No. 12/455,163 to Dewing (filed 29 May 2009), theteachings of which are hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention is concerned with swimming pools and spas, and inparticular with means of cleaning and removing debris from swimmingpools and spas.

2. Description of the Related Art

Swimming pool suction cleaning devices of the prior art typicallycomprise a rectangular housing having a substantially planar bottom witha centrally located suction hole connected to a suction means via a hoseattached to a tubular outlet on the housing top. The cleaning device ismoved along the pool bottom so that the housing bottom remainssubstantially parallel and in close proximity with the bottom of theswimming pool while water from the swimming pool is sucked through asmall bottom gap between the housing bottom and the swimming poolbottom. In some cases, wheels or housing bottom protrusions are used toprovide a bottom gap that is more uniform and/or optimum in width. Thehousing may also be made of a flexible material so that the housingbottom tends to conform to curved areas of the pool bottom. Such devicesare reasonably effective for removing dirt from the pool bottom butcannot efficiently capture debris larger than the bottom gap of thedevice. And the bottom gap is typically very small so as to provide thefast water flow rate needed to efficiently remove dirt from the swimmingpool bottom.

Various modifications designed to improve the effectiveness of poolcleaning devices have been described in the prior art. For example, U.S.Pat. No. 5,048,149 to Heinen (issued 17 Sep. 1991) describes a poolcleaning device having a fixed brush attached along the leading edge ofthe housing so as dislodge dirt particles by sweeping the pool surface.Such brushes tend to push debris along the pool bottom rather thandirect it to the suction hole.

Some pool cleaning suction devices of the prior art provide the needednarrow bottom gap via a lip around the perimeter of a housing bottomthat circumscribes a bottom suction cavity containing a means forimproving the effectiveness of the device. For example, U.S. Pat. No.5,842,243 to Horvath et al. (issued 1 Dec. 1998) describes a poolcleaning suction device having a fixed brush pivotally mounted inside abottom suction cavity such that the brush angle changes depending on thedirection of movement of the device. U.S. Pat. No. 4,402,101 to van Zyl(issued 6 Sep. 1983) describes a pool cleaner device comprising anelongated brush rotated by an electric motor and located inside thebottom suction cavity so that dirt dislodged by the sweeping action ofthe rotating brush is effectively captured by the device. U.S. Pat. No.6,942,790 to Dolton (issued 13 Sep. 2005) describes a pool cleaningsuction device having two cylindrical scrubbing brushes mounted insidethe bottom suction cavity that are rotated in opposing directions by amechanical drive motor.

Such prior art devices are ineffective for removing bits of debris thatare too large to pass through the narrow bottom gap between the housingbottom perimeter and the pool surface. Tree leaves are particularlydifficult to capture using the devices of the prior art since the leavesare often highly non-planar so that they do not readily pass through thesmall bottom gap needed to vacuum dirt from pool surfaces. Furthermore,tree leaves and other debris tend to hang up and accumulate at the inletto the suction hole and other sharp edges of prior art pool cleanerdevices.

U.S. Pat. No. 5,664,275 to Sebor (issued 5 Sep. 1997) describes a poolcleaning suction device having an oscillator that periodically widensthe bottom gap around the perimeter of a bottom suction cavity so as toperiodically capture larger bits of debris. The Sebor '275 device isrelatively complicated and does not provide continuous capture ofdebris.

U.S. Pat. No. 5,001,800 to Parenti et al. (issued 26 Mar. 1991)describes a pool cleaning suction device comprising a hydraulic turbinemotor that drives two pairs of wheels having rubber band treads toprovide locomotion, and drives a cam that raises one of the pairs oftreaded wheels off the pool bottom to provide steering. Parenti '800further describes use of the motor to drive rotation of a cylindricalbrush located along the front of the housing but does not indicate thatit provides improved effectiveness for capturing large bits of debris.The Parenti '800 device is relatively complicated and is not well suitedfor use in small residential swimming pools.

U.S. Patent Application Publication 2006/0174430 to Pareti (published 10Aug. 2006) describes a swimming pool cleaning device that includes anultrasonic wave generator in a housing bottom cavity designed todislodge adherent materials from the submerged pool surfaces. The Pareti'430 device further comprises an electric motor that drives rubbertreads via drive wheels to move the device along the pool surface, andthree rotary brushes. The larger brush is located within the housingbottom cavity and the two smaller brushes are located outside thehousing on the leading and trailing edges. The Pareti '430 device isdesigned to remove recalcitrant deposits, such as limestone scale, rust,sludge and weeds, via a combination of ultrasound and scrubbing. Thisdevice is relatively complicated and is not well suited for use in smallresidential swimming pools. The Pareti '430 publication provides noindication that the device provides improved effectiveness for capturinglarge bits of debris.

As evident from the examples above, most prior art efforts to improvepool cleaning devices have focused on removal of dirt and scale depositsrather than debris. Consequently, rotary brushes incorporated in priorart devices have typically been located within the suction cavity wherethey are ineffective as aids for capturing debris too large to directlypass through the bottom gap of the device. Prior art pool cleaningdevices also tend to be powered by an electric or hydraulic motor andoften include steering mechanisms, making them too bulky, complicatedand expensive for use in small residential swimming pools. There is aneed for a relatively simple pool cleaning device that effectivelyremoves both dirt and debris, especially tree leaves, from swimming poolbottoms.

Recent U.S. Patent Application Publication 2010/0299863 to Dewing(published 2 Dec. 2010) describes a manually operated pool cleaningdevice that is useful for removing both dirt and debris from a swimmingpool bottom. The Dewing '863 pool cleaning device comprises arectangular housing connected to a suction means via a hose; at leastfour transport wheels rotatably attached to the rectangular housing viatransport wheel axles so as to enable the pool cleaning device to berolled along the swimming pool bottom with the long housing sidesperpendicular to the direction of motion; two cylindrical rotary brusheseach rotatably attached via a brush axle to the housing along one of theopposing long housing sides such that the bristles of the cylindricalrotary brush contact the swimming pool bottom; and at least two rotarydrive mechanisms whereby rotation of the transport wheels, produced byrolling the pool cleaning device along the swimming pool bottom, drivesrotation of the cylindrical rotary brush on the leading edge of the poolcleaning device in the same rotational direction as the transportwheels. The rotary brush on the leading edge of the Dewing '863 poolcleaning device produces a downward sweeping action that tends toflatten tree leaves and other debris so that they can be sucked througha small bottom gap between the housing bottom planar area and theswimming pool bottom.

SUMMARY OF THE INVENTION

The present invention provides a pool cleaning device having anelliptically-beveled suction hole inlet and optionally other topologicalfeatures on the bottom of the device housing that facilitate smooth flowof water to and into the suction hole so as to improve capture of treeleaves and other debris from a submerged surface of a swimming pool or aspa. Optional topographical features that may be included in a device ofthe invention having a rectangular housing, comprise: sloped edges alongeach of the housing long sides such that the spacing between the housingbottom and the submerged surface of the pool is increased on the outsideedges of the housing perpendicular to the direction of motion tominimize the possibility of debris catching on the outer edge of thehousing bottom; and a bottom suction cavity designed to channel debristoward the elliptically-beveled suction hole inlet. The bottom suctioncavity may comprise sloped sides, especially along the short housingsides, and/or partitions to improve uniformity of water flow along thelong housing sides. Sloped suction cavity sides may be flat, curved orhave segments with different slopes. A device according to the inventioncomprising a cylindrical rotary brush mounted outside the housing alonga housing long side may further comprise a curved fender that partiallywraps around the top of the rotary brush so as to increase water flowthrough the bottom portion of the rotary brush to enhance capture ofdebris.

In a preferred embodiment, the device of the invention comprises: arectangular housing with two transport wheels attached to each shortside of the housing; a centrally-located suction hole with ahemiellipsoidal inlet whose long axis is substantially parallel with thehousing long sides; a suction cavity on the bottom of the housing havingsides that are sloped along the short housing sides to improve theuniformity of water flow along the housing long sides, and partitions todirect debris toward the hemiellipsoidal suction hole inlet; a tubularoutlet for connecting the suction hole outlet to a suction means via ahose; a pole attachment fitting enabling the pool cleaning device to berolled along the submerged surface of the pool with the long housingsides perpendicular to the direction of motion; two cylindrical rotarybrushes rotatably attached along the outside edges of the housing longsides; two rotary drive mechanisms whereby rotation of the transportwheels as the cleaning device is manually moved along the pool bottomdrives rotation of the cylindrical rotary brush on the leading edge ofthe pool cleaning device in the same rotational direction as thetransport wheels; sloped edges along each of the housing long sides suchthat the spacing between the housing bottom and the submerged surface ofthe pool is increased adjacent to the cylindrical brushes; and twocurved fenders each attached along one of the housing long sides so asto partially wrap around the top of one of the cylindrical rotarybrushes and increase water flow through the bottom portion of the brush.

The hemiellipsoidal suction hole inlet of the pool cleaning device ofthe invention is simple but highly effective for removing tree leavesand other debris, especially when combined with the other bottomtopographical features of the invention and a rotary brush along theleading edge of the device. The device may be designed to bemanually-operated or motor-driven so that it is well-suited for cleaningboth large and small swimming pools and spas.

Further features and advantages of the invention will be apparent tothose skilled in the art from the following detailed description, takentogether with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically depicts top (A), bottom (B) and side (C) views of abasic embodiment of the pool cleaning device of the invention wherein asubstantially constant bottom gap is maintained by means of spacersalong the short sides of a rectangular housing.

FIG. 2 schematically depicts top (A), bottom (B) and side (C) views of abasic embodiment of the pool cleaning device of the invention wherein asubstantially constant bottom gap is maintained by means of transportwheels on the short sides of a rectangular housing.

FIG. 3 schematically depicts top (A), side (B) and end (C) views of apreferred embodiment of the pool cleaning device of the invention.

FIG. 4 schematically depicts a bottom view (A) and an endcross-sectional view (B) of the preferred embodiment of the poolcleaning device of FIG. 3.

FIG. 5 shows computer-generated oblique (FIG. 5A) and perpendicular(FIG. 5B) views of the top of a prototype pool cleaning device accordingto the invention.

FIG. 6 shows computer-generated oblique (FIG. 6A) and perpendicular(FIG. 6B) views of the bottom of the prototype pool cleaning device ofFIG. 5.

These figures are not to scale and some features have been enlarged forbetter depiction. The housing is depicted in these figures as thoughtransparent to better illustrate details of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Terminology used in this document is generally known to those skilled inthe art. The term “rectangular housing” denotes the overall shape of thehousing rather than a rigid mathematical geometry. The generic term“pool” encompasses both swimming pools and spas. The terms“hemielliptically-beveled” and “hemiellipsoidal” are equivalent anddenote the overall shape of the beveled suction hole inlet rather than arigid mathematical geometry. The term “housing bottom planar area” alsoapplies to the same area when the housing bottom is curved so as toconform to the curvature of the swimming pool bottom. The term “debris”denotes any small object that may need to be removed from a swimmingpool, tree leaves, bits of paper, and candy wrappers, for example.

The term “rotatably attached” when applied to a wheel, gear or pulleyhaving an axle denotes that the wheel, gear or pulley may rotate aboutthe axle or that the axle may rotate, or both. Axles employed in thepool cleaning device of the invention may be rotatably attached tohousings, wheels, gears and pulleys in blind or through-holes via anysuitable means, including those selected from the group consisting ofslip fit, bushing, ball bearing, roller bearing, and combinationsthereof. Wheels, gears and pulleys may be retained on axles by anysuitable means, including those selected from the group consisting ofsplit ring, cotter pin, retaining nut, and combinations thereof. Theterm “fastened” denotes that a wheel, gear or pulley is firmly attachedso as to rotate with rather than around an axle. Wheels, gears andpulleys may be fastened to axles via any suitable means, including thoseselected from the group consisting of press fit, spline, cog, ratchetconnection, and combinations thereof. Such attachment, retaining andfastening devices are well known in the art and are not depicted in thefigures.

The present invention provides a pool cleaning device for removing dirtand debris from a submerged surface of a pool, comprising: a housinghaving a centrally-located suction hole with an elliptically-beveledinlet on the bottom of the housing and a tubular outlet on the top ofthe housing for connecting the suction hole to a suction means; a meansof moving the pool cleaning device along the submerged surface of thepool; and a means of maintaining a substantially constant bottom gapbetween the bottom of the housing and the submerged surface of the poolas the pool cleaning device is moved along the submerged surface of thepool. Other topological features may be included on the bottom of thedevice housing to facilitate smooth flow of water to and into thesuction hole so as to further improve capture of tree leaves and otherdebris from a submerged surface of a swimming pool or a spa.

The pool cleaning device of the invention may comprise a housing of anysuitable shape, a rectangle or a pentagon, for example, and may includespacers, wheels or both to provide a uniform bottom gap between thehousing bottom of the device and the submerged surface of the pool. Thedevice of the invention may further comprise one or more manually-drivenor motor-driven rotary brushes, preferably located outside the housingalong one of the housing sides. The device of the invention may be movedalong the submerged surface of a pool manually or by means of a motor.Preferably, the long axis of the hemiellipsoid defined by theelliptically-beveled suction hole is substantially perpendicular to thedirection of motion of the pool cleaning device over the submergedsurface of the pool.

FIG. 1 schematically depicts top (A), bottom (B) and side (C) views of abasic embodiment of a pool cleaning device of the invention, which has arectangular housing 121 with a centrally-located suction hole 112 havingan elliptically-beveled inlet 112 a and a suction fitting 122 forattaching to a suction means via a hose. Elliptically-beveled inlet 112a defines a hemiellipsoid having a bottom ellipse 112 b in the sameplane as housing bottom planar area 111 or a parallel plane thereto. Thehemiellipsoid defined by elliptically-beveled inlet 112 a may have anysuitable orientation and any suitable dimensions. The long axis of thehemiellipsoid is preferably oriented to be substantially perpendicularto the direction of motion of the pool cleaning device (parallel to thelong sides of a device with a rectangular housing). Bottom ellipse 112 bdepicted in FIG. 1 has a short axis that is substantially equivalent tothe diameter of suction hole 112.

For the device of FIG. 1, a substantially constant bottom gap 129 ismaintained between housing bottom planar area 111 and the submergedsurface of a pool by means of spacers 128 a and 128 b attached tohousing bottom planar area 111 along the short sides of housing 121.This basic device also includes a pole attachment fitting 123 having adepressible pin 124 for connecting to a pole, and is connected to thetop of housing 121 via a swivel pin 125 attached to the housing top viaattachment blocks 126 and 127. Any of the various pole attachmentfittings commercially available may be used with the pool cleaningdevice of the invention. A pole attachment fitting providing a steeringcapability to facilitate pushing the pool cleaning device back and forthin swaths covering the pool bottom is preferred. Tubular outlet fitting122 typically press fits to the suction hose but may be of any suitabletype, and may include a locking mechanism.

Any suitable suction means may be used with the pool cleaning device ofthe invention. A variety of suitable suction means are known in the art.Swimming pools are generally equipped with a skimmer and a filter pumpand the suction provided by this equipment is typically suitable for usewith the pool cleaning device of the invention. Typical water flow ratesare in the 25 to 70 gallons per minute range.

FIG. 2 schematically depicts top (A), bottom (B) and side (C) views of apreferred embodiment of the pool cleaning device of the invention which,similar to the device of FIG. 1, has a rectangular housing 221 with acentrally-located suction hole 212 having an elliptically-beveled inlet212 a and a suction fitting 222 for attaching to a suction means via ahose. This device also includes a pole attachment fitting 223 having adepressible pin 224 for connecting to a pole, and is connected to thetop of housing 221 via a swivel pin 225 attached to the housing top viaattachment blocks 226 and 227. The device of FIG. 2, however, includesfour transport wheels 231, 232, 233 and 234 attached via axles 231 a,232 a, 233 a and 234 a, respectively, to the short sides of housing 221,which enable the device to be rolled along the submerged surface of apool while a substantially constant bottom gap 229 is maintained. Notethat the first digit of the numbers used to designate the various partsof the device of the invention in the figures corresponds to the figurenumber and the last two digits are the same from figure to figure forsubstantially equivalent parts. Discussions of some parts may not berepeated for subsequent figures.

For the preferred device of FIG. 2, the length of the short axis ofbottom ellipse 212 b is smaller than the inside diameter of suction hole212. In this case, suction hole 212 is constricted by a step or lip 213so as to enhance water flow along the long axis of the hemiellipsoiddefined by elliptically-beveled inlet 212 a and provide more uniformwater flow along the long sides of housing 221. For optimum water flowuniformity, the long axis of bottom ellipse 212 b should be at leasttwice the inside diameter of suction hole 212, and the height of theinlet hemiellipsoid relative to housing bottom planar area 211 (or thetop surface of a bottom suction cavity) is preferably at least 5millimeters. The optimum shape and dimensions of the inlet hemiellipsoiddepend on the shape and dimensions of the device housing.

The pool cleaning device of the invention may include optionaltopographical bottom features that further improve the capture of treeleaves and other debris by the hemiellipsoidal suction hole inlet. Oneimprovement is provided by a sloped edge along at least one side of thehousing to provide a graded spacing between the housing bottom and thesubmerged surface of the pool on the leading edge of the pool cleaningdevice to minimize the possibility of debris catching on the outer edgeof the housing bottom. Additional improvement may also be provided by abottom suction cavity with or without one or more partitions to directthe flow of water and debris toward the elliptically-beveled suctionhole inlet. The top of the bottom suction cavity preferably comprisesinclined areas on either side of the suction hole that slope down tointersect the bottom planar area at an angle, reducing the depth of thesuction cavity near the short housing sides and improving the uniformityof water flow into the housing along the housing long sides. For poolcleaning devices with a cylindrical rotary brush along the leading edgeoutside the housing, a fender that is attached to the housing and wrapsaround the top of the rotary brush may be used to enhance capture oftree leaves and other debris by increasing water flow through the bottomportion of the brush.

A preferred embodiment of the pool cleaning device of the inventioncomprises: (1) a rectangular housing having two short and two longhousing sides; (2) a housing bottom with a centrally-located suctionhole having an elliptically-beveled inlet and sloped edges along each ofthe long housing sides; (3) a housing bottom suction cavity havingsloped sides along the housing short sides to improve uniformity ofwater flow along the housing long sides; (4) one or more partitionswithin the bottom suction cavity to direct the flow of water and debristoward the elliptically-beveled suction hole inlet; (5) a housing topwith a pole attachment fitting and a tubular outlet for connecting thesuction hole to a suction means via a hose; (6) at least four transportwheels rotatably attached to said rectangular housing via transportwheel axles so as to enable the pool cleaning device to be rolled alongthe submerged surface of the pool with the long housing sidesperpendicular to the direction of motion and the width of the bottom gapbetween the housing bottom and submerged surface of the pool remainingsubstantially constant; (7) two cylindrical rotary brushes each having abrush axle rotatably attached at both ends to said rectangular housingso as to be parallel with the transport wheel axles and adjacent to oneof the opposing long housing sides such that the bristles of saidcylindrical rotary brushes contact the swimming pool bottom; (8) atleast two rotary drive mechanisms whereby rotation of said transportwheels, produced by rolling the pool cleaning device along the submergedsurface of the pool, causes at least one of said cylindrical brushes torotate about its brush axle in the same rotational direction as saidtransport wheels; (9) two curved fenders each attached to saidrectangular housing along one of the housing long sides so as topartially wrap around the top of one of said cylindrical rotary brushes;(10) at least two and preferably four support wheels located on thehousing bottom around the periphery of the suction hole so as tomaintain the spacing between the housing bottom and the submergedsurface of the pool around the suction hole substantially uniform andconstant at the predetermined value; and (11) a sufficient amount ofweight, attached to said housing, to press said transport wheels againstthe swimming pool bottom with sufficient force to produce adequatelyfast rotation of said cylindrical rotary brushes. Tree leaves and otherdebris are effectively captured as the pool cleaning device, connectedto a suction means, is rolled back and forth over the swimming poolbottom by an operator pulling and pushing on a pole attached to the poleattachment fitting.

The housing of the pool cleaning device of the invention may beconstructed of any suitable material that is chemically compatible withpool water and provides adequate strength, durability and flexibility.The rectangular housing preferably comprises a polymer material that canbe readily molded and/or machined, and has sufficient flexibility toallow the housing bottom to at least partially conform to curvature ofthe swimming pool bottom. A preferred method of fabrication is injectionmolding.

FIG. 3 schematically depicts top (A), side (B) and end (C) views of apreferred embodiment of a pool cleaning device 300 according to theinvention, comprising a rectangular housing 301, four transport wheels331, 332, 333 and 334, two cylindrical rotary brushes 341 and 342, tworotary drive mechanisms 351 and 352 whereby rotation of transport wheels332 and 333 drives rotation of cylindrical rotary brushes 342 and 341,respectively. In FIG. 3 and subsequent figures, the rectangular housingis rendered as though transparent in order to better depict the rotarydrive mechanisms, wheel axles, cylindrical brushes and brush axles.Rectangular housing 301 has a housing bottom 311 with a bottom planararea and a centrally-located elliptically-beveled suction hole 312, anda housing top 321 with a pole attachment fitting 323 and a tubularoutlet 322 for connecting suction hole 312 to a suction means via ahose. Transport wheels 331, 332, 333 and 334 are attached in pairs tothe opposing short sides of rectangular housing 301 via transport wheelaxles 331 a, 332 a, 333 a and 334 a, respectively, so as to enable poolcleaning device 300 to be rolled along the submerged surface of a poolwith the long housing sides and the long axis of the hemiellipsoidalsuction hole inlet perpendicular to the direction of motion and thewidth of the bottom gap between the bottom planar area of housing bottom311 and the submerged surface of the pool remaining substantiallyuniform and constant at a predetermined value. Cylindrical rotarybrushes 341 and 342 have respective brush axles 341 a and 342 a that arerotatably attached at both ends to rectangular housing 301 so as to beparallel with wheel axles 331 a, 332 a, 333 a and 334 a and adjacent tothe opposite long housing sides such that the bristles of saidcylindrical rotary brushes contact the submerged surface of the pool.

As indicated in FIG. 3(C) for transport wheels 333 and 334, each of thetransport wheels of the pool cleaning device preferably comprises a huband a tire. The transport wheel tires preferably comprise a rubber-likematerial that provides good traction and is non-marking (does not leavemarks on the submerged surface of the pool). Any suitable rubber-likematerial may be used.

Any suitable type of rotary drive mechanism may be used, includingdirect drive, belt drive, gear drive, and combinations thereof. A beltor gear drive such that the rotary brushes rotate at a faster rate thanthe transport wheels, preferably at least 50% faster, is preferred. Therotary drive mechanisms of the invention preferably include a ratchetgear or ratchet pulley device such that rotation of the transport wheelscauses the cylindrical brush on the leading edge of the pool cleaningdevice to rotate but does not cause the cylindrical brush on thetrailing edge of the pool cleaning device to rotate. In this case, theforce required to move the pool cleaning device manually along the poolbottom is reduced without affecting the performance of the pool cleaningdevice. Suitable ratchet gear and ratchet pulley devices are well-knownin the art.

For the preferred pool cleaning device of FIG. 3, the rotary drivemechanisms comprise gear trains 351 and 352 comprising transport wheels332 and 333 and drive gears 351 a and 352 a respectively fastened totransport wheel axles 332 a and 333 a, intermediate gears 351 b and 352b rotatably fastened to housing 301 via intermediate gear axles, andbrush gears 351 c and 352 c respectively fastened to the axles ofbrushes 342 and 341. Rotation of the transport wheels causes the drivegears to rotate in the same rotational direction, the intermediate gearsto rotate in the opposite direction, and the brush gears and brushes torotate in the same rotational direction as the transport wheels. One ofthe gears in each of the gear trains is preferably a ratchet gear suchthat only the brush on the leading edge is caused to rotate by rotationof the transport wheels. The gear trains of the pool cleaning device maycomprise three coplanar gears, as depicted in FIG. 3, but mayalternatively comprise any suitable number of gears of any suitablediameters arranged in any configuration providing rotation of the rotarybrush on the leading edge of the pool cleaning device at a suitablerotation rate in the same rotational direction as the transport wheels.The term “gear” encompasses both gears with interlocking cogs, andsmooth gears engaged via friction.

The cylindrical rotary brushes may be any suitable diameter and maycomprise any suitable material or combination of materials. The brushbristles may comprise metallic wires, such as stainless steel, brass orbronze, but preferably comprise polymer strands. The brush axles, whichmay be solid cylinders or twisted strands, preferably comprise a metal,such as stainless steel, brass or bronze, but may comprise a polymermaterial, such as Nylon® or Delrin®. A suitable brush diameter is 3.2 cm(1.25 inches).

The preferred device of FIG. 3 further comprises curved fenders 371 and372 each of which is attached to rectangular housing 301 along one ofthe housing long sides so as to partially wrap around the tops ofcylindrical brushes 341 and 242, respectively, and increase water flowthrough the bottom portions of brushes 341 and 342 so as to enhancecapture of debris. Curved fenders 371 and 372 may be segmented, viaslits (not shown), for example, to enhance flexibility so that housing301 can better conform to the curvature of the submerged pool surface.Curved fenders 371 and 372 may be attached using fasteners, such asscrews, or may be an integral part of housing 301 formed by injectionmolding, for example.

For the preferred pool cleaning device of FIG. 3, housing bottom 311 issloped along the long sides of housing 301 so as to provide housingbottom sloped edges 381 and 382 such that the spacing between thehousing bottom and the submerged surface of the pool is wider adjacentto brushes 341 and 342 and tapers toward the long centerline of housing301. Housing bottom sloped edges 381 and 382 are designed to enhancecapture of debris, which would otherwise tend to hang up at the sharpbottom edges of housing 301. Housing bottom sloped edges 381 and 382 mayhave any suitable slope and may be planar or curved.

The preferred embodiment of FIG. 3 further comprises weights 361 and 362attached to housing 301. The amount of added weight should be sufficientto press the transport wheels against the submerged surface of the poolwith sufficient force to produce adequately fast rotation of thecylindrical rotary brushes. The amount of weight needed depends largelyon the suction force provided by the suction means employed. Weights 361and 362 may be attached to housing 301 using fasteners, such as screws,or may be integrated into housing 301, via injection molding, forexample. Weights 361 and 362 preferably comprise a relatively densemetal. The added weight may comprise any number of weights distributedin any suitable manner.

FIG. 4 schematically depicts a bottom view (A) and an endcross-sectional view (B), which better illustrate bottom features of thepreferred embodiment of the pool cleaning device of FIG. 3. The housingbottom planar area 411 circumscribes elliptically-beveled suction hole412 and defines a bottom gap between the housing bottom planar area 411and the submerged surface of the pool. The bottom gap should besufficiently uniform and narrow in width to provide the uniformly highwater flow rate needed to effectively remove dirt from the pool bottomand pull dirt and debris to the suction hole. The optimum bottom gapdepends on the size and specific shape of housing 401 and housing bottomplanar area 411, and on the suction means employed. A bottom gap ofapproximately 3 mm is typically suitable.

A preferred embodiment of the pool cleaning device of the inventioncomprises at least two and preferably four support wheels located on thehousing bottom around the periphery of the suction hole so as tomaintain the width of the spacing between the housing bottom and thesubmerged surface of the pool around the suction hole substantiallyuniform and constant at the predetermined value. Such support wheels areespecially useful for pool cleaning devices with housings that arerelatively wide and flexible, for which sagging of the housing due tosuction and gravity tends to reduce water flow locally and consequentlythe effectiveness of the pool cleaning device. Support wheels arepreferably located in wheel wells in the bottom of the housing that mayresult in wheel well protrusions on the top surface of the housing. Thepreferred pool cleaning device of FIGS. 3 and 4 comprises four supportwheels 491, 492, 493 and 494 (FIG. 4) in respective wheel wells 391,392, 393 and 394 (FIG. 3) that protrude above top surface 321 of housing301.

FIG. 4 also illustrates a preferred bottom suction cavity 480 having atrapezoidal cross-section defined by bottom planar area 411, inclinedsidewalls 483 and 484, and cavity top surface 485. Bottom suction cavity480 tends to provide a stream of water toward elliptically-beveledsuction hole 412 so as to enhance capture of debris. Suction cavity toparea 485 preferably comprises inclined areas 485 a and 485 b on eitherside of suction hole 412 that slope down to intersect bottom planar area411 at an angle. This reduces the depth of suction cavity 480 along theshort sides of housing 401 so that the uniformity of water flow into thehousing along the housing long sides is improved. Preferably, asindicated in FIG. 4, the segments 411 a and 411 b of bottom planar area411 that run along the short housing sides are also reduced in width tofurther improve the water flow uniformity along the housing long sides.

FIG. 4 also illustrates bottom partitions 495 and 496 that protrude intosuction cavity 480 from suction cavity top surface 485 and help directwater flow to elliptically-beveled suction hole 412 so as to enhancecapture of debris. Such bottom partitions may be of any suitable shapeand size. Bottom partitions preferably extend downward to besubstantially coplanar with bottom plane 411 so as to effectivelychannel water toward elliptically-beveled suction hole 412. Branchedbottom partitions have been found to be particularly effective.

Within the scope of the invention, the elliptically-beveled suction holemay be used alone or in combination with any of the other features ofthe invention, including a rotary brush, a rotary brush fender, ahousing bottom sloped edge, a bottom suction cavity and a housing bottompartition. The rotary brush may be continuous or segmented, and may besupported by intermediate brush axle supports. Intermediate brush axlesupports may be needed for relatively wide pool cleaning devices havingflexible housings and brush axles so that the housing bottom tends toconform to curvature of the pool bottom. A brush axle may also comprisetwo or more individual brush axle segments so as to increase theflexibility of a rectangular housing. Transport wheels and rotarycylindrical brushes may be attached directly to a housing or viacantilevered cross-beams that overhang the housing sides.

DESCRIPTION OF A PREFERRED EMBODIMENT

A preferred pool cleaning device according to the invention comprises arectangular housing with an elliptically-beveled suction hole and twotransport wheels attached to each of its short sides, a rotary brushadjacent to each of the housing long sides and driven by rotation of atransport wheel via a gear rotary drive mechanism that includes aratchet connection, four recessed support wheels located around theperiphery of the suction hole, two curved fenders each of which isattached to the housing and partially wraps around the top of one of thecylindrical rotary brushes, and a housing bottom that includes housingbottom sloped edges along the housing long sides, a bottom suctioncavity that comprises partitions and inclined top surface areas oneither side of the suction hole. The housing and the brush axles arepreferably flexible so that the pool cleaning device tends to conform tocurvature in the swimming pool bottom. For sufficiently wide devices,the flexible brush axle should be supported by intermediate brush axlesupports attached to the housing.

Prototype Pool Cleaning Device

FIG. 5 shows computer-generated oblique (FIG. 5A) and perpendicular(FIG. 5B) views of the top of a prototype pool cleaning device accordingto the invention. The housing 501 of the prototype device had fourtransport wheels 531-534 (two on each of the short housing sides) andtwo cylindrical rotary brushes 541 and 542 along each of the longhousing sides, each brush having two intermediate brush axle supports541 a/541 b and 542 a/542 b, respectively. The prototype devicecomprised two curved fenders 571 and 572 that partially wrapped aroundthe tops of cylindrical rotary brushes 541 and 542, respectively. Toincrease flexibility of housing 501 so that the device would betterconform to curvature in the submerged surface of the pool, fenders 571and 572 were divided into segments via slits (as indicated). Theprototype device further comprised eight attached weights 561-568 and acombination tubular suction hole outlet 522 and pole attachment fitting523 (FIG. 5A).

FIG. 6 shows computer-generated oblique (FIG. 6A) and perpendicular(FIG. 6B) views of the bottom of the prototype pool cleaning devicedepicted in FIG. 5. The bottom of housing 601 of the prototype devicecomprised a suction hole 612 with an elliptically-beveled suction holeinlet 612 b, four recessed support wheels 691-694 located around theperiphery of suction hole 612, sloped edges 681 and 682 along thehousing long sides, a bottom suction cavity 680 (having a trapezoidalcenter cross-section defined by bottom planar area 611, inclinedsidewalls 683 and 684, and top cavity area 685) that was divided bypartitions 695 and 696 along the centerline of the housing on eitherside of the suction hole. Partitions 695 and 696 further comprisedbranch partitions 695 a/695 b and 696 a/696 b, respectively, asindicated in FIG. 6. The top cavity area 685 had end sections 685 a and685 b that sloped down to bottom planar area 611 such that the width ofbottom planar area 611 along the short housing sides was minimal.

The rectangular housing of the prototype device was approximately 51 cmwide (long side not including the transport wheels), 19 cm long and 3.5cm tall (not including the hose connection (5.1 cm outside diameter)which extended 2.6 cm above the top of the housing). The prototypehousing was constructed of a resin photopolymer (mechanically similar toABS and BPT plastics) using a computer-controlled laser polymerizationprocess. A more flexible material is preferred for production devices.

The four transport wheels of the prototype device were 2.5 cm wide andhad an overall diameter of 8.5 cm (including a non-marking tire about1.0 cm thick), and were each attached to the housing via a transportwheel axle (1.5 cm diameter) and a plastic bushing. The four recessedsupport wheels were 1.4 cm wide and had an overall diameter of 3.4 cm,and were positioned around the suction hole as indicated in FIG. 6B. Thebottom gap between the bottom planar area and the submerged surface ofthe pool was 2.4 mm.

The cylindrical rotary brushes of the prototype device had an overalldiameter of 3.2 cm (1.25 inches) and comprised Nylon® bristles attachedto a non-metallic brush axle 3.0 mm in diameter. The cylindrical rotarybrushes were driven at 1.5 times the rotation rate of the transportwheels via rotary drive mechanisms comprising three Nylon® gears eachand including a ratchet connection.

The prototype housing included integral segmented curved fenders thatwrapped around the top of each cylindrical rotary brush withapproximately 3 mm clearance between the curved fenders and the brushbristles. The housing bottom long edges were sloped at 17° over adistance of 1.6 cm so that the spacing between the housing bottom andthe submerged surface of the pool increased to 3.2 mm adjacent to thecylindrical rotary brushes.

The housing bottom of the prototype device included a rectangular bottomsuction cavity approximately 3 mm deep (relative to the bottom planararea) whose sides sloped up from the insides of the bottom planar area(51 cm×16 cm) to a rectangular top cavity area (31 cm×7 cm). The bottomsuction cavity was divided by two branched partitions coplanar with thebottom planar area (see FIG. 6) on either side of the suction holeinlet. The width of the bottom planar area was 3 mm along the housinglong sides and minimal along the housing short sides.

The suction hole of the prototype device had an inside diameter of 4.4cm, which was reduced in the elliptically-beveled region to 3.6 cm by anoverhang of the elliptical bevel. The hemiellipsoid defined by theelliptically-beveled suction hole inlet had a depth of approximately 2.0cm (relative to the suction cavity top area) and its bottom ellipse hada short axis of 3.6 cm (0.4 cm lip on two opposite sides of the suctionhole) and a long axis of 15.1 cm.

The prototype device was shown to be highly effective for removing treeleaves and other debris from the submerged surfaces of a swimming pool.Those skilled in the art will appreciate that some benefit according tothe invention could be provided by elliptical suction hole inlets havinga wide range of dimensions (hemiellipsoid depth and bottom ellipse shortand long axes), and the optimum configuration and dimensions will dependon the type and size of the pool cleaning device.

The preferred embodiments of the present invention have been illustratedand described above. Modifications and additional embodiments, however,will undoubtedly be apparent to those skilled in the art. Furthermore,equivalent elements may be substituted for those illustrated anddescribed herein, parts or connections might be reversed or otherwiseinterchanged, and certain features of the invention may be utilizedindependently of other features. Consequently, the exemplary embodimentsshould be considered illustrative, rather than inclusive, while theappended claims are more indicative of the full scope of the invention.

1. A pool cleaning device for removing dirt and debris from a submergedsurface of a pool, comprising: a housing having a centrally-locatedsuction hole with an elliptically-beveled inlet on the bottom of thehousing and a tubular outlet on the top of the housing for connectingthe suction hole to a suction means; a means of moving the pool cleaningdevice along the submerged surface of the pool; and a means ofmaintaining a substantially constant bottom gap between the bottom ofthe housing and the submerged surface of the pool as the pool cleaningdevice is moved along the submerged surface of the pool, whereby treeleaves and other debris are more effectively captured as the poolcleaning device, connected to a suction means, is moved along thesubmerged surface of the pool.
 2. The pool cleaning device of claim 1,wherein the housing bottom has a sloped edge along at least one side ofthe housing to provide a graded spacing between the housing bottom andthe submerged surface of the pool on the leading edge of the poolcleaning device to minimize the possibility of debris catching on theouter edge of the housing bottom.
 3. The pool cleaning device of claim1, wherein the housing has a bottom suction cavity.
 4. A pool cleaningdevice for removing dirt and debris from a submerged surface of a pool,comprising: a rectangular housing having two short and two long housingsides, a housing bottom with a housing bottom planar area and acentrally-located suction hole having an elliptically-beveled inlet, anda housing top with a pole attachment fitting and a tubular outlet forconnecting the suction hole to a suction means via a hose; and at leastfour transport wheels rotatably attached to said rectangular housing viatransport wheel axles so as to enable the pool cleaning device to berolled along the submerged surface of the pool with the long housingsides perpendicular to the direction of motion and the width of thebottom gap between the housing bottom and submerged surface of the poolremaining substantially constant, whereby tree leaves and other debrisare effectively captured as the pool cleaning device, connected to asuction means, is rolled back and forth over the swimming pool bottom byan operator pulling and pushing on a pole attached to the poleattachment fitting.
 5. The pool cleaning device of claim 4, wherein twoof said transport wheels are attached to each of the opposite housingshort sides.
 6. The pool cleaning device of claim 4, further comprising:at least two and preferably four support wheels located on the housingbottom around the periphery of the suction hole so as to maintain thespacing between the housing bottom and the submerged surface of the poolaround the suction hole substantially uniform and constant at thepredetermined value.
 7. The pool cleaning device of claim 4, wherein thehousing bottom has sloped edges along each of the long housing sides toprovide a graded spacing between the housing bottom and the submergedsurface of the pool on the leading edge of the pool cleaning device tominimize the possibility of debris catching on the outer edge of thehousing bottom.
 8. The pool cleaning device of claim 4, wherein thehousing comprises a bottom suction cavity having a top surface.
 9. Thepool cleaning device of claim 8, wherein the top surface of the suctioncavity comprises inclined areas on either side of suction hole thatextend to the housing bottom planar area.
 10. The pool cleaning deviceof claim 8, wherein the bottom suction cavity comprises one or morepartitions to direct the flow of water and debris toward theelliptically-beveled suction hole inlet.
 11. The pool cleaning device ofclaim 4, further comprising: two cylindrical rotary brushes each havinga brush axle rotatably attached at both ends to said rectangular housingso as to be parallel with the transport wheel axles and adjacent to oneof the opposing long housing sides such that the bristles of saidcylindrical rotary brushes contact the swimming pool bottom; and atleast two rotary drive mechanisms whereby rotation of said transportwheels, produced by rolling the pool cleaning device along the submergedsurface of the pool, causes at least one of said cylindrical brushes torotate about its brush axle in the same rotational direction as saidtransport wheels, whereby tree leaves and other debris are moreeffectively captured due to a downward sweeping action produced byrotation of the cylindrical rotary brush on the leading edge as the poolcleaning device, connected to a suction means, is rolled back and forthover the submerged surface of the pool by an operator pulling andpushing on a pole attached to the pole attachment fitting.
 12. The poolcleaning device of claim 11, further comprising: two curved fenders eachattached to said rectangular housing along one of the housing long sidesso as to partially wrap around the top of one of said cylindrical rotarybrushes and increase water flow through the bottom portion of the brushso as to enhance capture of tree leaves and other debris.
 13. The poolcleaning device of claim 11, further comprising: a sufficient amount ofweight, attached to said housing, to press said transport wheels againstthe swimming pool bottom with sufficient force to produce adequatelyfast rotation of said cylindrical rotary brushes.
 14. The pool cleaningdevice of claim 11, wherein said rotary drive mechanisms are geared suchthat said cylindrical brushes rotate at a rotational rate that isgreater than the rotational rate of said transport wheels.
 15. The poolcleaning device of claim 11, wherein said rotary drive mechanismsinclude a ratchet connection such that rotation of the transport wheelscauses the cylindrical brush on the leading edge of the pool cleaningdevice to rotate but does not cause the cylindrical brush on thetrailing edge of the pool cleaning device to rotate.
 16. The poolcleaning device of claim 11, wherein the brush axles and the housing areflexible so that the housing bottom tends to conform to curvature of theswimming pool bottom.
 17. The pool cleaning device of claim 11, whereineach of the brush axles is supported at one or more intermediatelocations between the ends of the brush axle by one or more brush axlesupports fastened to said rectangular housing.
 18. The pool cleaningdevice of claim 11, further comprising: at least two cantileveredcross-beams perpendicular to the long sides of said rectangular housing,wherein the axles of said transport wheels and said cylindrical rotarybrushes are rotatably connected to the ends of said cantileveredcross-beams.
 19. The pool cleaning device of claim 11, wherein each ofthe brush axles comprises two or more individual brush axle segments soas to increase the flexibility of said rectangular housing so that thehousing bottom can better conform to curvature of the swimming poolbottom.
 20. A pool cleaning device for removing dirt and debris from asubmerged surface of a pool, comprising: a rectangular housing having ahousing bottom with a centrally-located suction hole with anelliptically-beveled inlet, and a housing top with a tubular outlet forconnecting the suction hole to a suction means; at least four transportwheels rotatably attached to said rectangular housing so as to enablethe pool cleaning device to be moved along the submerged surface of thepool with the width of the bottom gap between the housing bottom andsubmerged surface of the pool remaining substantially constant; at leastone cylindrical rotary brush whose bristles contact the submergedsurface of the pool; and at least one electrical motor that drivesrotation of at least one of the transport wheels, at least one of therotary brushes, or both.